There is widely known a method of controlling a power plant (a steam turbine) with a controlled bleed and counterpressure. According to this method, electrical energy is produced by a gas flow one part of which is partially discharged from the controlled bleed chamber, whereas the other part is directed from the power plant to the controlled counterpressure header. According to the method under review, a control signal to control the pressure downstream of the power plant (in the controlled counterpressure header) is applied to a control element which controls the flow rate of gas supplied to the high-pressure section of the power plant. The signal to control the pressure in the controlled bleed chamber is also applied to said control element for controlling the flow rate of gas directed to the high-pressure section of the power plant.
The control signal to control the pressure downstream of the power plant is also applied to another control element to control the flow rate of gas directed to the low-pressure section of the power plant. The control signal of the electric load of the electric generator, i.e. a pulse carrying information on the rotation speed of the power plant's rotor, is applied to the control element which controls the flow rate of gas supplied to the high-pressure section of the power plant in order to raise the rotation speed of the power plant's rotor.
The method under review does not make it possible to automatically control a power plant operating under conditions when there are independent programs according to which power is produced and gas is supplied at a predetermined pressure to the heat engines which power the gas compressors.
There is widely known a power plant of a compressor station of a gas main with gas pumping units including gas compressors and combustion chambers of gas turbine installations. The power plant under review comprises an electric generator having a power take-off chamber and intended to meet the power requirements of the compressor station, and an expansion engine whose shaft is coupled to that of said electric generator. The inlet of the expansion engine is connected through a heater and a control element, installed at the inlet of said expansion engine, to the gas main. The outlet of the expansion engine is connected to the combustion chambers of the gas turbine installations which power the gas compressors.
Similar power plants are provided with a line including a control member and bypassing the foregoing units.
However, the above power plant only meets the power requirements of the compressor station depending on the amount of gas supplied to the heat engines which power the gas compressors.
In case of a limitation in or a complete stop of the fuel gas supply due to an emergency situation at the compressor station, the foregoing power plant either limits or completely stops the production of electrical energy. In such situations, the use of other types of power producing equipment to meet the power requirements of the compressor station involves serious difficulties and considerably affects the operating reliability of the compressor station. For that reason, none of the existing autonomous compressor stations incorporates a power plant of the foregoing type despite its obvious thermodynamic effectiveness.